With emphasis on the use of coal as an energy source, a problem of increasing concern is the transporting and handling of coal during periods of extreme cold. More particularly, coal carried by hopper cars freezes into large masses which are difficult to dump and which cause damage to equipment such as belts, rollers, etc., utilized in coal dumping facilities.
Various approaches to the solution of this problem have previously been proposed. For example. in U.S. Pat. No. 1,212,252--which issued to Menotti Pellegrino on Jan. 16, 1917, a plurality of spear-like elements are lowered into a coal car while the exterior of the car is simultaneously struck by hammers. The intended effect is to loosen coal within the car. However, such an arrangement has the important shortcoming of causing damage to the hopper car.
Another method disclosed in the prior art is that described in U.S. Pat. No. 3,181,799 which issued on May 4, 1965 to Warren F. Wurzburg et al. This patent relates to an arrangement wherein frozen coal is loosened by applying high intensity vibrational energy to the coal. More particularly, such energy is produced by an electrically operated transducer which develops ultrasonic energy for vibration purposes. However, such an arrangement would appear to require the application of a tremendous amount of power in order to effectively loosen frozen coal within a hopper car.
A still further prior art arrangement is that disclosed in U.S. Pat. No. 2,108,416 which was granted to Abraham E. Smith et al on Feb. 15, 1938. This patent is concerned with a method of loosening material within a railway car by permanently installing agitating devices in the car which are actuated to loosen the car contents. Obviously, such an arrangement is expensive and probably is not suitable for use with large masses of material such as frozen coal.